For passenger safety and convenience, most automobile interiors are equipped with lamp assemblies. The bulbs, structural frames, parabolic reflectors and wiring components comprising these lamp assemblies are typically recessed into cavities in the automobile headliner, door panels, and other interior surfaces, allowing them to be completely covered by a bezel and lens assembly. In most applications, the lens is a generally planar member, tinted or frosted both to diffuse light and to hide the recessed components. To focus, instead of diffuse light, while still hiding the recessed components, some lenses have a Fresnel surface on the interior lens face. The bezel, most often manufactured of metal or opaque plastic, serves both as a frame for the lens and as a styling means to visually and texturally blend the typically smoother exterior lens surface with the coarser fabric material often covering the surrounding mounting surface.
For aesthetic purposes, the outside surface of the lens is often polished. Although providing for satisfactory illumination, these polished lenses are very susceptible to scratching, and are therefore more costly to store and handle during manufacture, than unpolished lenses. Furthermore, when installed in automobile interiors and subjected to normal wear, these delicate polished surfaces become scratched and nicked, losing both their luster and their aesthetic appeal.